1. Field of the Invention
This invention relates generally to a flexible closure panel and, more particularly, to a type thereof adapted for closing a substantially rectangular opening in a wall by a winding up and winding off action, said closure being operable to close the respective opening and being secured against leaving its lateral guides.
2. Discussion of the Prior Art
There are numerous closure structures, especially for openings in a building. One such closure is disclosed in U.S. Pat. No. 4,175,608 to Alten which uses a closure body adapted to be wound up and off and is characterized primarily in that the securing elements are detachably connected to the rim portions of the closure body, adapted to be conveyed to the closure body to be wound off, and are adapted to be withdrawn from the closure body to be wound off.
Another door structure is disclosed in U.S. Pat. No. 4,478,268 to Palmer which discloses a door for closing vehicular traffic passages in which the door is a curtain fabricated from a hard flexible material. The curtain runs in opposing channels, is mounted on a counterbalanced wind-up drum and under impact changes weight, moves out of the channel and is wound up to open the vehicular passage.
U.S. Pat. No. 3,460,602 to Hugus discloses a flexible closure tensioning device employing a flexible membrane fastened to a bottom rail which is movable towards and away from an upper roller on which the membrane wraps and unwraps itself as the closure opens and closes. The device includes a spring and cable system co-acting together with the upper roller and the bottom rail away from the roller, whereby tension is applied to the flexible member in all positions of the lower marginal edge of the latter.
U.S. Pat. No. 3,878,879 to Manns discloses a roll-up door wherein the door-leaf is flexible and arranged to be wound about a roller into open position. The door-leaf is maintained in a stretched condition laterally by means of trolleys having grooved wheels running in contact with guide rails provided in vertical side frames. The weight of the door-leaf may be completely balanced, making it possible to operate the door manually.
The use of flexible panels as closure members, such as doors for relatively large openings in buildings has been severely restricted by the size of the opening. In a common procedure for opening and closing this type of door, an elongated cylinder, often a hollow shaft, is located at the upper edge of the opening and the flexible panel is rolled upon the shaft when the door is opened. However, where the door is of extensive width, and or the door opening is especially high, serious problems are encountered in effecting support of the panel supporting cylinder between the ends thereof. Regardless of the measures taken, it has been heretofore necessary to physically engage the panel on the cylinder at the lower surface thereof at intervals along the cylinder and, obviously, this has resulted in excessive wear at the locations of such support. Furthermore, because of the concentration of pressure between the support means, such as rollers, and the fabric rolled on the cylinder, a puckering or gathering of the panel during the rolling or unrolling thereof from the cylinder has not only increased the wear, but often has given the panel an unsightly appearance. Previous attempts, as shown by the prior art, have been largely self defeating. Attempts to make the cylinder or shaft entirely supported at its ends have resulted in excessive increases in the weight of the shaft, hence its supporting structure.
In addition to the self-defeating aspect of previous attempts to solve the problem, such attempts have always resulted in an increase in cost which has been substantial and usually unacceptable.
Accordingly, it is an object of this invention to improve the above mentioned doors in such a way that the closure body can be wound up to a roll of relatively small diameter.
A further object of this invention is to provide a simple, flexible, closure device for various size and shape openings.
A still further object of this invention is to provide a roll mechanism with a guide track which seals out undesired matter or insects.
Yet another object of this invention is to provide a closure device which can be opened and closed easily by manual, remote or automatic means.
These and other objects of the invention will become apparent to those skilled in the art to which the invention pertains when taken in light of the annexed drawings.